When I was a kid in New Jersey in the 1970s, I seem to recall there
was some sort of referendum, or ballot, or initiative, or bill, or
some other genuine effort to officially break the state of New Jersey
up into two separate states (North and South).  I know that the
demographics and culture of north Jersey and south Jersey are about as
different as two separate states can be, so this doesn't sound
entirely surprising, but I do not have any specific information about
whether this really happened, how far it went, what the results were,
etc.  Can you please tell me whether this was proposed, under what
circumstances, how far it went and what the results were?

Hello rickw,

There was an effort to split six South Jersey counties from the rest of the state.

"On Election Day in 1980, 51 percent of voters in six South Jersey
counties declared in a non-binding referendum that they wanted to
secede and establish a new state ....

The secession vote had no official weight.  It essentially was a
megaphone-scale opinion poll that caught Trenton's attention ...."

Google cache of "Across The Great Divide," by Kevin Coyne (Jan. 2005)
New Jersey Monthly
http://64.233.167.104/search?q=cache:8XAZRluKmIIJ:www.njmonthly.com/issues/Jan05/gdivide.html

- justaskscott

Search strategy --

After some trial and error, I found the page I've cited with the
following search on Google:

"north jersey" "south jersey" referendum

JustAskScott got me the basic information I was looking for.  Thank you.